Electric heater for stock watering tanks



NOV. 27. 1951 J, T, LANDGRAF 2,576,688

ELECTRIC HEATER FOR STOCK WATERING TANKS Filed Jan. 8. 1948 PatentedNov. 27, 1951 2,576,688 ELECTRIC HEATER FOR STOCK WATERING TANKS JacobT. Landgraf, Freeport, 111., assignor to H. D. Hudson ManufacturingCompany, Chicago, 111., a corporation of Minnesota Application January8, 1948, Serial No. 1,237

8 Claims.

This invention relates to a new and improved portable electric heaterunit for application to stock Watering tanks and the like.

The principal object of my invention is to provide an immersion typeheater of the kind mentioned designed for quick and easy, as well assecure, fastening to the side wall of a tank, whether it be of steel orconcrete construction, and to transfer heat to the water in a horizontalplane at a depth of about eighteen inches, or less, below the surface,so as to insure maintaining in cold weather an unfrozen opening in thevicinity of the heater large enough for drinking purposes. Importantfeatures of this heater are as follows:

(1) The L-shape of the copper tube heatin coil, in which the electricalheating element is housed, facilitates secure attachment to the, sidewall of the tank, and enables heat transfer from the enlarged horizontalloop on the lower end of the coil in the horizontal plane at the desireddepth, and predetermines more or less the location and area of theunfrozen opening, besides reducing to a minimum the danger of stockupsetting or damaging the heater when drinking.

(2) The substantially parallel vertical legs of the heating coil areattached at their upper ends to the switch housing, in which a switch ismounted, and this switch is operated mechanically by a thermostat, theheat sensitive capsule part of which is disposed between the lower endportions of said legs and clamped thereto by heat conducting plates,whereby automatically to maintain at least in the zone of the heater 9.water temperature of about 42 F., while the heater is in use on a tank,and automatically to break the circuit through the unit at a like lowtemperature, to avoid accidentally burning out the heating element, andalso wasting current, if the unit happens to be left connected to acurrent source when the tank is empty or nearly so or when the heater isnot in use in a water-filled tank, as, for example, after having beendemonstrated by a salesman, or when being first tried out by a farmer atthe time of delivery, or when it may be later carelessly mishandled byan unskilled farm-hand. r (3) A vertical sheet metal shield is fastenedat its upper end to the switch housing and encloses the vertical legs ofthe heating coil and serves to protect the animals against contact withthe hot coil while the unit is in operation in a tank, and excludes acertain amount of trash and dirt fromthe coil and the thermostat.

The invention is illustrated in the accompanying drawing, in which- Fig.l is a vertical section through a portion of a stock watering tank ofsteel construction showing, in side elevation, a heater made inaccordance with my invention applied thereto;

Fig. 2 is a rear view of the heater removed from the tank;

Fig. 3 is a top view of the heater with the cover of the switch housingremoved to show the switch therein and its connections with theelectrical heating element in the heating coil;

Fig. 4 is a section on the line 4-4 of Fig. 2, to show the heatconducting mounting of the thermostats capsule on the heating coil;

Fig. 5 is an enlarged section on the line 55 of Fig. 3, to show theoperating connection between the thermostat and the switch, and

Fig. 6 is a sectional detail showing the method of attaching the heaterof Figs. 1-5 to a concrete tank.

Similar reference numerals are applied to corresponding parts.

' Referring to Figs. 1-5, the reference numeral 1 designates theelectric heater of my invention shown applied to the rim 8 of a steeltank 9. The heater 1 comprises a generally L-shaped heating coil Incontaining an electrical heating element, indicated diagrammatically inFig. 3 in dotted lines at II, that is connected at one end, as shown at12, with one terminal of the micro-switch l3. The latter is mounted on aframe [4 which is bolted, as at I5, in a switch housing IS. The coil l0has its two ends entered in and suitably rigidly secured to the housingI5, so that the electrical connections between the heating element l land switch 13 can be enclosed in said housing. A flexible conduit I!attached to the bottom of the housing 16 contains two wires 18 and I9,one of which is connected to the other end of the heating element l Iand the other to the remaining terminal of switch l3. A third wire 20extending through the conduit IT is grounded, as at 2!, to the switchhousing I6 at its inner end and is suitably connected at its outer endto a pipe or rod driven into the ground, whereby to provide a thoroughlyreliable ground connection in case of insulation failure in the heater.The switch [3 is closed by a predetermined downward movement of itsplunger 22, and, contrariwise, is opened by a predetermined upwardmovement of said plunger. A thermostat consisting of a capsule 23connected by means of a small tube 24 with a collapsible and expansiblebellows in the housing 25 is arranged to operate cordingly for a giventemperature. The tempera ture controller is of a well known type andforms no part of my invention, excepting only in so far as it and itsassociated thermostat 23-25 cooperate in a novel manner with theassociated ele-- ments of the heating unit of myqinvention. A cap orcover '23 fits down over the rim of the housing l6 to enclose the switch[3 and the asso ciated mechanism against damage by the animals and forprotection against rain or snowor any moisture, and is fastened byscrews that thread i in holes 3| in the housing. It should be clear fromthe description thus far that,.assuming the thermostat capsule 23 issubjectto the rise and fall intemperature of the water in the tank 9,

the circuit for the heating element. H in coil ||l will be opened andclosed by means of switch l3 operated in response to said thermostat,whereby to maintain a substantially constant temperature inthe, wateraround the coil ID.

A U-sh'aped attaching bracket 32 isinverted and bolted by itscross-portion to the bottom of the housing l6,'as indicated at 33, andis of a size to fit freelyover the rim 8 of the tank 9, as shown in.Fig. 1. A thumb screw ,34, threaded in a hole in the outer portion ofthe bracket extends below therim 8 and can be tightened in abutment withthe side wallof the tank to clamp the heater firmly and securely inplace on the tank. Then a e ut 35 threading. on the thumb screw 34, canbe tightened against the bracket 32, to lock the screw againstaccidental loosening. It is obvious at with t is oun ing here is no,danger of the heater being upset and damaged by the stock when drinking,and the farmer does not have to uild an in on the tank to. a mmodatethis heater, as was the case with some others with which I amv familiar;this heater comesready toinstall and is made to fit the existing tanks.In the case of concrete tanks, likethat indicated at M in Fig. ,6, whichare not nearly as common as I steel tanks, it is necessary to builda,small inverted. L-shaped wooden-- bracket 36 to rest on top of the sidewall, as shown, providing laterally Spaced substantially parallel sidepieces 31 and, 38 with a cross-piece 39 fastened between their innerends for the bracket 32 to straddle and be clamped on, using the thumbscrew Stpreviously mentioned.

With either installation, it will be seen that; the L-shape of theheating coil l0 not only facilitates the secure attachment of the unitto the side-wall of the tank. but it insures heating of the water in ahorizontal plane bythe wideelongated hori zontal loop 40- at the desireddepth in relation to the top of the tank 9 or 911 topredetermine more orless the location and area of the unfrozen opening through which thestock can drink at any timeregardless of the weather.- Ifthe tank has ahog-drinker in it, the heater i should be located so'that one side ofthe loop 40 touches it. That will prevent freezing of thewater inthe hogdrinker, r

Y The substantially parallel-and closely spaced vertical legs-4| of theheating coil iii are enclosed the maj portion .oftheimength 1.11.1.2.channel-.1

shaped sheet metal shield 42, which has inturned longitudinal flanges42a on the back thereof to prevent displacement from the legs 4| andwhich is fastened at its upper end, as indicated at 43, to thedownwardly projectin flange 44 on the bottom of the housing It. Thisshield protects the animals against contact with the hot coil while theunit is in operation in a tank, and it also excludes a certain amount oftrash and dirt from the coil and its associated thermostat. The capsule23 of the thermostat projects down below the lower end of the shield 32,so as to be maintained at a temperature close to the temperature of thewater surroundingv the loop 40. This capsule is clamped in amideposition between and parallel to the. legs 4| by means of two sheetmetal plates 45 and 46, which are disposed in cross-wise relation to thecapsule 23 and legs 4|, with their opposite end portions enclosed in theside portions of the channel-shaped shield 42 behind the flanges. 42a,these plates, being heldin tight engagement with the three parts 234| bytwo bolts 41 disposed on opposite sides of the capsule 23. The bolts 41,therefore, also positively space the capsule 23 from the legs 4| of theheater. This positive positioning of the capsule is very important,because if the capsule were to be brought into contact with either leg4|of the heater or be disposed in too close proximity thereto, the heaterwould not be controlled properly and the water would, most likely,freeze in cold weather. There is, however, a further and almost equallyimportant reason for this method of assembling the capsule in'theheater, and that is to avoid having the heating element burn out-if theunit happens to be left connected to a current source when not in use ina water-filled tank, as, for example, if it has been demonstrated by asalesman, or when it is first being tried out by a farmer at the time ofdelivery, or when it may be later carelessly mishandled by an unskilledfarm-hand. Under these conditions, the plates 45 and 46 con duct enoughheat from the legs 4| to the capsule 23 to break the circuit through theheating element in the coil I0 at about 42 R, which is the temperatureat whichv the thermostat maintains the water when the unit is inoperation in a tank. The coil ID will, of; course, heat up tothat temperature quickly when exposed to the air and the current will then bepromptly shut off by reason of the heat conductedfrom; thecoil: |0through the plates 45' and 43 to the capsule 23.. At that lowtemperature there is no dangerof the heating element being burned out,and, 0f

Goursathere is also much less current consumpa 1 tion.

Itis believed theforegoing description conveys a d u rstanding ftheobiects and advan: tages of my invention. The appended claims havebeen drawn to cover all legitimatemodificae tions and adaptations.

I claim:

1. An immersion type tank heater comprising a generally 'L-shapedheating coil of rigid metallic tubing including a substantiallyhorizontal loop and two spaced substantially parallel upright endportions extending from the endsof-saidloopin rigid substantially rightangle relationship there to and adapted to serve as supports-for thecoil, a housing attached to the upperends of said upright end portionshaving a bracket attached thereto for detachable connection with the rimof a tank for supporting said coil by means of the housing on the sidewallof a tank the 'fiuid contents of which'are to be heated, an electricheating element in at 'least thehorizontal loop portion'ofsaid heatingcoil, switch means in the housing connectedwith said heating elementtocontrol current flow thereto from a source of electric current supply, ashield for the upright end portions of the coil extending down from thehousing, and thermostatic means responsive to change in the temperatureof the fluid contents of. the tank connected for openin and closing saidswitch means and including a temperature responsive part to be heatedimmersible in the fluid with the horizontal loop of the heating coil buthoused within and protected by said shield.

2. An immersion type tank heater comprising a generally L-shaped heatingcoil of rigid metallic tubing including a substantially horizontal loopand two spaced substantially parallel upright end portions extendingfrom the ends or said loop in rigid substantially right anglerelationship thereto and adapted to serve as supports for the coil, ahousing on the upper ends of said upright end portions containing aswitch, an electric heating element in at least the horizontal loopportion of said heating coil electrically connected in an electriccircuit with said switch, so that the switch controls current flowthrough said heating element from a source of current supply, a bracketon the housing for detachable connection with the'rim of a tank, wherebythe housing supports the heating coil in the tank, and a thermostatmechanically connected with the switch in the housing and having athermally responsive element extending downwardly from said housing outof contact with the upright end portions of the coil for immersion ofits lower end portion in the fluid so as to be heated thereby.

3. An immersion type tank heater comprising a generally L-shaped heatingcoil including a substantially horizontal loop and two spacedsubstantially parallel upright end portions extendin from the ends ofsaid loop, a housing on the upper ends of said upright end portionscontaining a switch, an electric heating element in said heating coilelectrically connected in an electric circuit with said switch, so thatthe switch controls current flow through said heating element from asource of current supply, attaching means on said housing for mountingsaid heater on the side wall of a tank the fluid contents of which areto be heated, a sheet metal shielding enclosure for the upright endportions of said heating coil attached at its upper end to the housingfor support, a thermostat of the bulb and capillary tube type disposedbetween the upright end portions of said heating coil and thereforeprotected also by the shielding enclosure, means mechanically connectingthe thermostat at its upper end with the switch in said housing, thebulb of said thermostat being disposed lowermost for immersion in thefluid in the tank, whereby to operate the switch in response totemperature change of the fluid, and means spacing the bulb from theupright end portions of the heatin coil.

4. An immersion type heater comprising a generally L-shaped heating coilincluding a substan tially horizontal loop and two spaced substantiallyparallel upright end portions extending from the ends of said loop, ahousing on the upper ends of said upright end portions containing aswitch, an electric heating element in at least the horizontal loopportion of said heating coil electrically connected in an electriccircuit with said switch, so that the switch controls current flowthrough said heating element from a source of current supply, a bracketon the housing for detachable connection with the rim of a tank, wherebythe housing supports the heating coil in the tank, a thermostat ofelongated form and vertically disposed substantially in parallelism withthe up.- right end portions of said coil and having the lower end inproximity to the plane of the horizontal loop portion of the coil so asto be immersed in the fluid being heated by said coil and having theupper end operatively connected with said switch to make and break thecircuit in response to temperature change so as to maintain the fluid ata predetermined temperature, and a heat conductor mechanicallyconnecting said thermostat and a lower portion of said heating coil soas to subject the thermostat to temperature rise in direct proportionwith the heating coil when it is disposed in space, said heat conductorbeing so located on the heater as to be immersed in the fluid to beheated with the heating coil and thermostat, whereby under normaloperating conditions the fluid abstracts heat therefrom to make thethermostat responsive to temperature change in the fluid.

5. An immersion type tank heater comprising a generally L-shaped heatingcoil including a substantially horizontal loop and two spacedsubstantially parallel upright end portions extending from the ends ofsaid loop, a housing on the upper ends of said upright end portionscontaining a switch, an electric heating element in said heating coilelectrically connected in an electric circuit with said switch, so thatthe switch controls current flow through said heating element from asource of current supply, a thermostat mounted on said heater so that itis immersed in the fluid .to be heated with the heating coil, saidthermostat being operatively connected with said switch to make andbreak the circuit in response to temperature change so as to maintainthe fluid at a predetermined temperature, attaching means on saidhousing for mounting said heater on the side wall of a tank the fluidcontents of which are to be heated, a sheet metal shielding enclosure ofchannelshaped section fitting over the upright end portions of saidheating coil on that side away from the side wall of the tank andattached at its upper end to the housing for support, said thermostatincluding an elongated part adapted to be heated by immersion in thefluid and disposed between the lower end portions of the upright endportions of said heating coil, whereby the same is subjected to the heatof the fluid in the vicinity of the horizontal loop portion of said coiland yet is shielded by said sheet metal enclosure, a pair of spaced heatconducting plates in contact at their opposite ends with the lower endportions of the upright end portions of said heating coil and also withthe elongated thermostat part intermediate their ends, and a pair oflaterally spaced bolts disposed on opposite sides of the elongatedthermostat part clamping the plates to the coil and to the elongatedthermostat part while positively spacing said thermostat part from bothend portions of the coil.

6. An immersion type heater as set forth in claim 4, including anelongated sheet metal shield which is vertically disposed and adapted tocover that side of the upright end portions of the heating coil awayfrom the side wall of the tank and secured at its upper end to thehousing for support, said shield having inwardly bent edge portionscontacting the upright end portions of said heating coil and alsocontacting the heat conductor, whereby said shield serves both todissipate heat from the heating coil to the atmosphere by radiation whenit is disposed in space and also help to conduct heat from the heatingcoil to the heat conductor when the heating coil is disposed in space.

- 7. An immersion type tank heater comprising a generally L-shapedheating coil including a substantially horizontal loop and twospacedsubstantially parallel upright end portions extending from theends of said loop, a housing on the upper ends of said upright endportions containing a switch, an electric heating element in saidheating coil electrically connected in an electric circuit withsaidswitch, so that theswitch controls current flow-through said heatingelement from a source of current supply, attaching means on said housingfor mounting said heater on the side wall of a tank the fluid contentsof which are to be heated, a sheet metal shieldingrenclosure for theupright end portions of said heating coil attached at its upper end tothe housing for sup port. a thermostat having an elongated part adaptedto be heated by immersion in'the fluid and disposed between the uprightend portions of said heating coil and therefore protected also by theshielding enclosure, means operatively connecting the thermostat withthe switch in said housing, whereby to operate the switch in response totemperature change of the fluid, and means fixedlyv spacing theelongated heatable part of the thermostat from the upright end por tionsof the heating coil.

8. An immersion type tank heater comprising a generally L-shaped heatingcoil including a substantially horizontal loop and two spacedsubstantially parallel upright end portions extending from the ends ofsaid loop, a housing on the upper ends of said upright end portionscontaining a switch, an electric heating element in said heating coilelectrically connected in an electric circuit with said switch, sov thatthe switch con trols current flow through said heating element from asource of current supply, attaching means on said housing for mountingsaid heater on the side wall of a tank the fluid contents of which areto be heated, a sheet metal shielding enclosure for the upright endportions of said heating coil attached at its upper end to the housingfor sup-- port, a thermostat of elongated form disposed substantiallyvertically inside said shielding, enclosure having its lower end portionarranged for immersion in the fluid, and means operatively connectingthe thermostat with the switch to operate the latter in response totemperature change of the fluid,

JACOB T. LANDGRAF.

REFERENCES CITED The following references are of record in the file ofthis patent:

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